McConnell cited working with the California Democrat to craft a deal on a highway bill last year. He said the pair “enjoyed each other’s company after many years of being on the opposite sides of everything.”

Boxer, first elected to the Senate in 1992, is retiring after this year , but has said she wants to remain active in politics.

McConnell was elected to the Senate in 1984, but said Monday he does not have plans to retire, telling Hugh Hewitt's radio show that there is a "good possibility" he will run again in 2020. "I feel like I’m at the top of my game," McConnell said.